1. Field of the Invention
This invention relates generally to multiple ply wood veneer composite articles having successive plies adhesively bonded to each other with the wood grain of the plies oriented generally parallel to each other.
2. Description of the Prior Art
The formation of multipiece wood articles of various configurations and for various purposes including tubular configurations and container type uses has been known for many decades. Illustrative of such prior art knowledge are the following U.S. Pat. Nos. 1,293,208; 2,267,888; 2,291,426; 2,296,781; 2,334,619; 2,719,808; and 3,437,547.
Among the problems experienced in connection with joining single layer wood pieces or employing single wood pieces or constructing tubular wooden articles out of a single thickness is the difficulty in forming a relatively thick single piece of wood. Also, such constructions are frequently subject to warpage, possess inadequate strength and are extremely difficult to form in small diameters. U.S. Pat. No. 1,293,208 illustrates an elongated tubular wooden article requiring the use of a number of single layer circumferential wood segments in order to establish a circumferentially continuous article.
It has also long been known to create multiple ply wood elements consisting of a number of wooden layers adhesively bonded to each other with adjacent layers having their grain orientations essentially perpendicular to each other. This has been found to increase the strength of the composite article. Typical of such prior art usages are the common plywood and the form of barrel shown in U.S. Pat. No. 2,267,888.
It has also been known to provide for composite structures by spirally winding or convolutely winding individual plies in such a fashion that adjacent plies are angularly disposed with respect to each other. See generally U.S. Pat. Nos. 2,296,781 and 2,334,619. As a result of the difficulty encountered in forming these prior art constructions to the desired configuration in a reliable, repeatable fashion, coupled with the uneconomic aspects of certain forms of prior constructions, the use of wood in tubular articles of various types, including containers, has been diminishing through the years and other materials including glass, plastic, various forms of paperboards and metals used solely or in combination have, to a substantial extent, displaced the use of wood in such articles. This is true in spite of the fact that wood provides both aesthetic and functional benefits as contrasted with some of these other materials. There remains, therefore, a need for a tubular article composed of multiple ply wood elements which may be economically produced and will perform effectively in terms of both aesthetic and functional considerations.